Conventional bearing apparatuses including bearing surfaces that move relative to one another are known in the art. For example, conventional, so-called “thrust bearings” and some embodiments of radial bearings include bearing surfaces that at least partially contact and move or slide relative to one another. Such bearing surfaces may include a superhard material for resisting wear during use of the bearing. In one example, diamond (e.g., polycrystalline diamond) may comprise at least one or both of the bearing surfaces.
More particularly, one application for thrust bearings is drilling equipment utilized in the subterranean drilling arts. Particularly, drilling motors have been utilized for drilling boreholes into a subterranean formation, especially for oil or gas exploration. In a typical downhole drilling motor, the motor is suspended at the lower end of a string of drill pipe comprising a series of pipe sections connected together at joints and supported from the surface. A rotary drill bit (e.g., a fixed cutter drill bit, roller cone drill bit, a reamer, etc.) may be supported below the drilling motor (via pipe sections, drill collars, or other structural members as known in the art) or may be directly connected to the downhole motor, if desired. Drilling fluid, which is commonly called drilling mud, is circulated through the pipe string and the motor to generate torque within the motor for causing the rotary drill bit to rotate. Then, the drilling fluid is returned to the surface through the annular space between the drilled borehole and the drill string and may carry the cuttings of the subterranean formation to the surface. Further, as known in the art, downhole drilling motors may include thrust bearings. More particularly, conventional downhole drilling motors include a stator that does not rotate and is connected to a housing of the motor and a rotor that rotates with the output shaft of the downhole fluid motor. In one embodiment, the stator and the rotor are each provided with a plurality of hard bearing surfaces such as diamond elements. The stator and rotor are positioned adjacent one another so that the diamond bearing surfaces of the rotor and stator contact one another. As may be appreciated, proper alignment of the diamond surfaces of the rotor and the stator may be an important factor influencing the performance and life of such a thrust bearing structure. Examples of conventional diamond thrust bearings are disclosed by U.S. Pat. Nos. 4,410,054, 4,468,138, and 5,092,687.
Thus, it would be advantageous to provide improved bearing apparatuses and systems including same.